National Variation in Implementation of Sentinel Lymph Node Biopsy for Clinically Node-Positive Patients Undergoing Neoadjuvant Therapy.

Background: Sentinel lymph node biopsy (SLNB) is feasible in women with clinically node-positive breast cancer following neoadjuvant chemotherapy and a nodal pathologic complete response. Acceptable false negative rates are achieved through technical considerations such as removing three or more sentinel lymph nodes (SLNs); however, the variation that exists in adherence to this technique is unclear.

Objective: This study aimed to evaluate recent trends in axillary surgery in women with cN1-cN2 disease who received neoadjuvant chemotherapy, adherence to removing three or more SLNs, and variation in SLN yield.

Methods: We performed a cohort study using the National Cancer Database of women aged ≥18 years with cN1-cN2 disease who received neoadjuvant chemotherapy, including those without a pathologic complete response, from 2012 to 2020. Trends in axillary surgery and lymph node yield obtained during SLNB were evaluated.

Results: The cohort included 67,365 women (median age 54 years). The number of patients receiving SLNB alone increased from 14 to 39%; SLNB with completion axillary lymph node dissection (ALND) increased from 17 to 30%; and ALND alone decreased from 69 to 27%. The rates of obtaining three or more SLNs during SLNB remained the same over time at 66%, while facility-level variation in obtaining three or more nodes ranged from 40 to 86%.

Conclusions: There has been de-escalation of axillary surgery with fewer patients undergoing ALND; however, overall there has been no significant change in the rates of obtaining three or more lymph nodes during SLNB following neoadjuvant chemotherapy, with significant facility-level variation observed.